1. Field of the Invention
The present invention relates to a method of preserving the color of stored meat using noble gases.
2. Description of the Background
Meat products, such as beef, veal lamb, mutton and pork are susceptible to a variety of degradative processes. For example, they are susceptible to attack by bacteria. Meat products are also quite susceptible to enzymatic degradation. For example, fats in meat products are readily hydrolyzed to fatty acids, which are, in turn, oxidized to produce a rancid odor. Further, proteins in meat products generate various nitrogen-containing compounds upon spoilage, such as ammonia and amino-group containing compounds which are characterized by a pungent and unpleasant odor.
At present, a variety of methods are known for preserving meat products in order to preserve the same from spoilage. However, such methods are generally neither intended nor designed to preserve the color of red meat, and/or generally entail complex process schemes, which tend to be commercially impractical.
For example, Japanese Patent Application No. 52-27699 discloses a method of treating frozen food which entails i) freezing livestock, marine and agricultural products in an isotropic press state at more than atmospheric pressure; ii) preserving these products at atmospheric pressure by freezing and refrigerating; and iii) heating and thawing these products in an isotropic press state at more than atmospheric pressure in order to eat the same. In this process, the freezing of products under pressure is described as being essential in order to preclude breakage of cell walls in the product being preserved. A similar rationale is set forth for thawing under pressure.
U.S. Pat. No. 4,946,326 describes the use of a gas mixture containing carbon dioxide, oxygen and argon to extend the shelf-life of fresh fish or sea food products at low temperature. However, this patent does not pertain to preserving of the color of red meat.
U.S. Pat. No. 4,522,835 describes a process for preserving color in meat, poultry and fish products, which entails i) reducing the products to change the red oxymyoglobin on or below the surface thereof to visually-perceptible purple myoglobin, and then ii) subjecting the products to an atmosphere containing from 0.10% to 3% by volume of carbon monoxide to convert the visually-perceptible purple myoglobin to visually-perceptible red carboxymyoglobin to a specified depth below the product surface. Thus, this process requires the use of a reduction step and then uses hazardous carbon monoxide to treat the products in a subsequent step.
Further, Japanese patent 77027699 discloses a process for maintaining the flavor of food by necessarily freezing and storing the food under pressure by introducing carbon dioxide, nitrogen, argon and hydrogen. However, this patent clearly does not address the deterioration of meat color that attends the use of conventional methods of meat preservation.
Generally, a description of controlled/modified atmosphere/vacuum packaging of foods is provided by A. L. Brody. See Controlled/Modified Atmosphere/Vacuum Packaging of Foods. Food and Nutrition Press, Inc.
Additionally, various methods have been advanced for the use of mixed gases to prevent the growth of anaerobic bacteria and mold.
For example, Japanese patents 52105232 and 80002271 both disclose the packaging of food to prevent spoilage by mold growth and anaerobic bacteria, respectively, using a mixture of argon and carbon dioxide. Also, Japanese Patent No. 1,059,647 describes the use of a mixture of argon and carbon dioxide to prevent the growth of mold. However, none of these patents addresses the deterioration of meat color.
EPA 422,995 discloses a method to preserve fresh food products such as fruit or vegetables comprising two steps: an initial step wherein the said products are refrigerated in a gaseous atmosphere comprising 10% to 100% of nitrous oxide and/or argon, but without oxygen followed by a second step wherein the products are maintained at about the same refrigerated temperature in an atmosphere comprising from 2% to 20% oxygen.
EPA 289,777 discloses the preservation of cut and segmented fresh fruit pieces in a container wherein the container is flushed with an oxygen-containing gas mixture, having preferably between about 5 and 50% oxygen and the rest being inert gases such as nitrogen, helium, argon and hydrogen. No description or suggestion is made in this patent application regarding the preservation of the color of red meat.
French Patent 1,339,669 discloses a stabilization process of products which might be altered by air during the treatment or storage thereof in closed containers. The products are particularly biological products, such as those used in human or veterinary medicine. This process is characterized by the fact that the products are maintained in the presence of a rare gas atmosphere, preferably argon. However, there is neither a description nor a suggestion in this patent regarding the preservation of meat color. Kocys and Venskevicius (1970) Mokslas Tech. 11:60-1. Chu et al. (1987) J. Food Sci 52:869-75, are studies of color stability of frozen beef under nitrogen and describe some typical inadequacies of this treatment, but neither describe nor suggest any improvements.
GB 1,392,580 discloses the packaging of fresh meat in a first oxygen-permeable layer, with a second oxygen-impermeable layer thereon, so that when packed in an inert atmosphere, the product remains isolated from oxygen until the impermeable layer is removed. The dual packaging extends the shelf-life of the meat.
U.S. Pat. No. 3,102,819 describes a method of tenderizing freshly slaughtered meat, which entails immersing the meat in a liquid nitrogen bath, pulverizing the embrittled meat in a gaseous nitrogen atmosphere, molding the meat into a slab, raising the temperature to coalesce the slab and then freezing the slab again for storage and shipment.
U.S. Pat. No. 4,919,955 discloses a method for processing fresh meat, which like U.S. Pat. No. 3,102,819, entails several complex processing steps.
Despite the existence of various methodologies for extending the shelf-life of fresh meat, none of these affords a means by which the color of red meat or meat products may be preserved in a commercially practical manner.
Therefore, a need exists for a means by which the color of red meat or meat products may be preserved in a commercially practical manner.